Process for producing unsaturated carbamic acid esters

ABSTRACT

The present invention provides a manufacturing method for unsaturated carbamic acid esters by allowing an unsaturated amide compound to react with a metallic base in an inert solvent, followed by a reaction with a halogenated formic acid ester. 
     The invention also provides a manufacturing method of unsaturated carbamic acid esters by allowing an urethane derivative to react with a metallic base in an inert solvent, followed by a reaction with an unsaturated acid halide.

This is a continuation application of Ser. No. 07/952,643, filed Sep.28, 1992, now abandoned, which in turn is a divisional of applicationSer. No. 07/723,271, filed Jun. 28, 1991, now U.S. Pat. No. 5,187,306.

FIELD OF THE INVENTION

The present invention relates to a novel process for producingunsaturated carbamic acid esters represented by the following generalformula: ##STR1##

(wherein R denotes a hydrogen atom or a lower alkyl group and R¹ denotesa residue obtained by subtracting a hydroxyl group from a monohydricalcohol.)

BACKGROUND OF THE INVENTION

The inventors of the present invention have already developedunsaturated carbamic acid esters represented by the general formulabelow and the use applications thereof (Japanese Patent Laid-OpenPublications No. 61-275259, 61-275260 and 61-275270): ##STR2##

(wherein R and R¹ are the same as mentioned above.)

The unsaturated carbamic acid esters are produced, as are disclosed inthe foregoing patent laid-open publications, by allowing the unsaturatedamide compounds represented by a general formula (1) to react with theoxalyl chloride (where R and R¹ denote the same meanings as the ones tobe described hereinafter) ##STR3## to synthesize a compound representedby a general formula described below and having an isocyanate group inthe molecule, ##STR4## followed by a reaction of the latter compoundwith alcohols (R¹ OH). This producing method is conducted by steps,because the isolation of the intermediate compounds having an isocyanategroup is required. To simplify this synthetic procedure into one-step ispractically difficult. Moreover, this producing method has a problemthat the handling is very difficult because the intermediate compoundshaving an isocyanate group to be isolated are highly reactive.

SUMMARY OF THE INVENTION

Accordingly, an essential object of the present invention is to providea process for producing unsaturated carbamic acid esters which areimportant compounds in the chemical materials, represented by thegeneral formula [I]. The process is indicated by two reaction steps, butthe reaction steps proceed continuously in one reaction vessel.

Another important object of the present invention is to provide amanufacturing method for unsaturated carbamic acid esters in whichhandling of the starting materials and reaction products are made easy.

In accomplishing these and other objects, according to one preferredembodiment of the present invention, there is provided a process forproducing unsaturated carbamic acid esters represented by the followinggeneral formula of ##STR5##

(wherein R denotes a hydrogen atom or a lower alkyl group and R¹ denotesa residue obtained by subtracting a hydroxyl group from a monohydricalcohol), wherein the unsaturated amide compounds represented by thegeneral formula of ##STR6##

(wherein R denotes a hydrogen atom or a lower alkyl group) are allowedto react with metallic bases in inert solvents, followed by the reactionwith the halogenated formic acid esters represented by the followinggeneral formula: ##STR7##

(where X denotes a halogen atom and R¹ denotes a residual group obtainedby eliminating a hydroxyl group from a monohydric alcohol)

The present invention also provides a process for producing unsaturatedcarbamic acid esters represented by the general formula [I], whereinurethane derivatives represented by the general formula of ##STR8##

(where R¹ denotes the same meaning as the ones in the above-describedformula) are Allowed to react with metallic bases in inert solvents,followed by the reaction with the unsaturated acid halides representedby the following general formula: ##STR9##

(where R and X denote the same meanings as the ones in theabove-described formulae)

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in detail hereinafter startingwith Process 1.

Process 1

The unsaturated amides which are the starting materials of the processesin the present invention are commercially available and are representedby the following general formula: ##STR10##

(where R denotes hydrogen or a lower alkyl group) In the formula, Rpreferably denotes hydrogen or a lower alkyl group having 2 to 5 carbonatoms, more preferably hydrogen or a methyl group. Typical examples ofthe unsaturated amide compounds are acrylamide, methacrylamide, and thelike.

First, the above-mentioned unsaturated amide compounds are allowed toreact with the metallic bases in the inert solvents, thereby forming themetal salts of the unsaturated amides. Metallic bases are recognized toinclude metallic compounds which exhibit basic properties or basicmetals per se. The metallic bases include hydroxides (e.g. potassiumhydroxide, sodium hydroxide, calcium hydroxide, magnesium hydroxide andaluminum hydroxide), carbonates (e.g. sodium carbonate and calciumcarbonate), hydrides (e.g. sodium hydride and calcium hydride),alkylates (e.g. methyl lithium and n-butyl lithium), alkoxide compounds(e.g. sodium alkoxide and lithium alkoxide) and metals (e.g. sodium,lithium and potassium). These compounds can be used alone, or they areused as a mixture. The amount of the compounds used for the reactions isnot limited, but it is in the range of 1 to 10 equivalent and preferablyin the range of 2 to 5 equivalent. The inert solvents used for thereactions are not limited unless they have any effects on the reactions.Typical examples of the solvents include aliphatic hydrocarbons such aspentane, hexane and heptane; aromatic hydrocarbons such as benzene,toluene and xylene; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane and decalin; petroleum solvents such as petroleum ether andpetroleum benzine; halogenated hydrocarbons such as carbontetrachloride, chloroform and 1,2-dichloroethane; ethers such as ethylether, isopropyl ether, anisole, dioxane and tetrahydrofurane (THF);ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone,cyclohexanone, acetophenone and isophorone; esters such as ethyl acetateand butyl acetate; acetonitrile; dimethyl formamide (DMF); and dimethylsulfoxide. These solvents are used alone or in the form of the mixedsolvent. Preferred solvents to be used in this invention have adielectric constant in the range of 3 to 40, examples of which are THF,dioxane, methyl isobutyl ketone, dichlorobenzene and DMF. The reactionsare made to proceed in the temperature range from -10° C. to 120° C. for0.5 to 10 hours. The metal salts of the unsaturated amides are possibleto be isolated. Since the order for mixing between the isolated metalsalts of the unsaturated amides and acid chlorides is not limited, it ispreferable for the continuous processing that the reactions are made toproceed by adding the halogenated formic acid ester (2) to the reactionsolution without isolating the salts of the unsaturated amides.

The halogenated formic acid ester represented by the following generalformula: ##STR11##

(where X denotes a halogen atom, preferably chlorine or bromine, and R¹denotes the residual group in which a hydroxyl group is eliminated froma monohydric alcohol) is obtained from the reaction of phosgene withalcohols (R¹ OH). In Formula (2), R¹ denotes for example alkyl,cycloalkyl, allyl, aralkyl, alkaryl, alkenyl, and alkynyl (carbonnumbers of these groups are in the range of 1 to 27 and 48) groups andtheir halogen substituents. R¹ also includes alkyl, cycloalkyl, allyl,aralkyl, alkaryl, alkenyl and alkynyl groups having carbon number of 1to 27 and molecular weight of 15 to 800, which are replaced with variouskinds of substituents directly or through carbonyl, ether or thioethergroups.

Typical examples of the applicable halogenated formic acid estersinclude metyl chloroformate, propyl chloroformate, butyl chloroformate,isobutyl chloroformate, 2-ethylhexyl chloroformate, sec-butylchloroformate, 2-methoxyethyl chloroformate, 2-ethoxyethylchloroformate, 2-butoxyethyl chloroformate, phenoxyethyl chloroformate,butoxyethoxyethyl chloroformate, methoxybutyl chloroformate, allylchloroformate, propargyl chloroformate, cinnamyl chloroformate,2-chloroethyl chloroformate, 1-chloroethyl chloroformate,trichloromethyl chloroformate, benzyl chloroformate, acetoxymethylchloroformate, methoxycarbonylmethyl chloroformate, tetrahydrofurfurylchloroformate, ethyl chloroformate.

The reaction temperatures of the above-described reactions are notlimited, but they are usually in the range of -20° to 100° C.,preferably 0° to 50° C. Reaction times are difficult to specify becausethey depend on the reaction temperatures and reactivity of the reagentsused for the reactions. Preferred reaction time is in the range of 0.5to 15 hours, and further preferably in the range of 1 to 7 hours.Reaction temperature of 100° C. or more tends to cause side reactionsand too low reaction temperature is not preferable since reaction rateis lowered.

The above halogenated formic acid esters (2) and the unsaturated acidhalides to be described in the following Process 2 react with metalbases vigorously. Accordingly, simultaneous mixing of these halogenatedcompounds and metallic bases with the amide compounds are difficult; thereaction yields will be lowered when these three kinds of compounds aremixed at the same time.

Polymerization inhibitors can be added in the reaction mixtures to avoidundesirable polymerizations at the terminal double bonds. Examples ofthe polymerization inhibitors include hydroquinone, p-methoxyphenol,2,6-di-t-butyl-4-methylphenol, 4-t-butylcatechol, bis-dihydroxybenzylbenzene, 2,2'-methylenebis(6-t-butyl-3-methylphenol),4,4'-butylidenebis(6-t-butyl-3-methylphenol),4,4'-thiobis(6-t-butyl-3-methylphenol), p-nitrosophenol,diisopropylxantogen sulfide, N-nitrosophenylhydroxylamine ammonium salt,1,1-diphenyl-2-picrylhydrazine, 1,3,5-triphenylpherdazyl,2,6-di-t-butyl-α-(3,5-di-butyl-4-oxo-2,5-cyclohexanediene-1-ilidene-p-trioxy,2,2,6,6-tetramethyl-4-piperidone-1-oxyl, dithiobenzoylsulfide,p,p'-ditolyltrisulfide, p,p'-ditolyltetrasulfide, dibenzyltetrasulfide,tetraethyltiuramdisulfide and phenothiazine.

The products are purified by the conventional method to obtain thecrystalline or oily compounds.

Process 2

The second process in the present invention is characterized in that theurethane derivatives represented by the general formula: ##STR12##

(where R¹ denotes the same meaning as the ones in the above-describedformulae) are allowed to react with the metallic bases in the inertsolvents, followed by the reaction with the unsaturated acid halidesrepresented by the following formula. ##STR13##

(where R and X denote the same meanings as the ones in theabove-described formulae)

The urethane derivatives used in the present invention are derived fromthe reactions among ammonia, phosgene and alcohols. Examples of theseurethane derivatives include ethyl carbamate, propyl carbamate, butylcarbamate, sec-butyl carbamate, butoxyethyl carbamate and ethoxyethylcarbamate.

The unsaturated acid halides represented by the general formula (4)include acrylic acid halide, methacryl acid halide, and the like, andthe preferable halogen atom is chlorine or bromine.

As are described in Process 1, the above unsaturated acid halides areallowed to react with the urethane derivatives in the presence of themetallic bases in the inert solvents. The reaction conditions areidentical with those described in Process 1.

The carbamic acid esters manufactured by the methods in the presentinvention are useful for starting compounds or intermediates of variouskinds of materials. They are particularly important as monomers forsynthetic polymer materials.

Thus, the manufacturing methods disclosed in the present invention makeit possible to produce the unsaturated carbamic acid esters inindustrial mass-production scale with simple manufacturing process,providing one step method for the synthetic procedure instead of theconventional two step process. Handling of the starting materials andfinal products is made easy.

EXAMPLES

Embodiments of the present invention will be described further referringto the examples. It is not intended that the scope of the presentinvention appended hereto be limited to the description as set forthherein, but rather it is understood that various other modificationswill be apparent to and can be readily made by those skilled in the artwithout departing from the scope and spirit of this invention.

Example 1

In 41 g of dioxane, 2.5 g of methacrylamide and 1.18 g of NaOH weredissolved and the solution was stirred for 1.0 hour at the temperatureof 25° to 27° C. Then, 4.0 g of ethyl chloroformate was dissolved in 10g of dioxane and the solution was added to the reaction mixture at once.After stirring the solution for 15 minutes, water was added thereto andthe solution was neutralized by adding conc. hydrochloric acid andfiltered. The filtrate was extracted with chloroform and the extract wasevaporated in vacuo. The crude product was subjected to columnchromatography for purification, thereby obtaining 0.841 g of ethylN-methacryloylcarbamate. Melting point (mp.) of the compound was 73°-74°C.

Example 2

In 52 g of dioxane, 12.5 g of methacrylamide and 1.0 g of sodiumethoxide (NaOEt) were dissolved and the solution was stirred for 20minutes at the temperature of 27° C. Then, 4.0 g of ethyl chloroformateacid was dissolved in 2 g of dioxane and the solution was added in twoportions into the above reaction solution. After leaving it for one day,the solution was neutralized with conc. hydrochloric acid and wasextracted with chloroform. The extract was evaporated in vacuo. Thecrude product was subjected to column chromatography, thereby obtaining0.44 g of ethyl N-methacryloylcarbamate. Melting point of the compoundwas 73°-74° C.

Example 3

In 200 g of dioxane, 4.26 g of methacrylamide and 6.37 g of potassiumt-butoxide were dissolved and the solution was stirred for 60 minutes at60° C. Then, 5.43 g of ethyl chloroformate was dissolved in 50 g ofdioxane and the solution was added dropwise to the reaction mixture in 2hours. After removing tetrahydrofurane in vacuo, 1000 g of water wasadded to the residue and the solution was extracted with 500 ml of ethylacetate. The extract was evaporated in vacuo. The crude product wassubjected to column chromatography, thereby obtaining 1.0 g of ethylN-methacryloylcarbamate. Melting point of the product was 73°-74° C.

Example 4

In 100 g of dioxane, 10 g of methacrylamide and 14.4 g of sodiumhydroxide were dissolved and the solution was stirred for 30 minutes at25°-27° C. Then, 16.6 g of ethyl chloroformate was dissolved in 30 g ofdioxane and the solution was added dropwise to the reaction mixture in 3hours while keeping the reaction temperature of 25° to 30° C. Afterstirring the solution for 20 minutes, water was added thereto and thesolution was neutralized with conc. hydrochloric acid. The solution wasextracted with chloroform and the extractant was evaporated in vacuo.The crude product was subjected to NMR assay and 17.2 g of ethylN-methacryloylcarbamate was isolated.

Example 5

After washing 2.5 g of sodium hydride with hexane, 10 g of dioxane wasadded to the residue. Then, 5.0 g of methacrylamide was dissolved in 32g of dioxane and the solution was added dropwise to the first dioxanesolution. After stirring the solution for 1.5 hours, 2.36 g of NaOH wasadded. A solution of 6.98 g of ethyl chloroformate in 10 g of dioxanewas added dropwise to the reaction mixture in about 3 hours whilekeeping the reaction temperature at 25°-27° C. After stirring thesolution for 30 minutes, water was added thereto and the solution wasneutralized with hydrochloric acid. The solution was extracted withchloroform and the extractant was evaporated in vacuo. The crude productwas subjected to NMR assay and 7.3 g of ethyl N-methacryloylcarbamatewas isolated.

Example 6

After washing 7.1 g of sodium hydride with hexane, 100 g of dioxane wasadded to the residue. Then, 15.0 g of methacrylamide was dissolved in 32g of dioxane and the solution was added dropwise to the first solution.After stirring it for 2 hours, 9.56 g of ethyl chloroformate wasdissolved in 30 g of dioxane and the solution was added dropwise to thereaction mixture in about 3 hours while keeping the reaction temperatureat 25°-27° C. After stirring the solution again for 30 minutes, waterwas added thereto and the solution was neutralized with hydrochloricacid. The solution was filtered and extracted with chloroform. Theextract was evaporated in vacuo. The crude product was subjected to NMRassay and 13.7 g of ethyl N-methacryloylcarbamate (in acid chloridestandard) was isolated.

Example 7

After washing 2.0 g of sodium hydride with hexane twice, 10 g of dioxanewas added to the residue. A solution of 4.28 g of methacrylamide in 34 gof dioxane was added dropwise to the first solution and the mixedsolution was stirred for 2 hours. The resultant slurry was filtered andthe filtrate was evaporated in vacuo, obtaining sodium salt of the amide[IR(cm⁻¹) 3400, 3190, 1660, 1600, 1480, 1450, 1410, 1240, 1050, 930,850, 620; ¹ H NMR (DMSO) (ppm) CH₃ CH₃ 5.41, 4.83 CH₂ ═C, 1.8 CH₂ ═C.Formation of methacrylamide salt was confirmed from the observation thatthe broad absorption band at 1450 cm⁻¹ in IR spectra is absent in thestarting material and NMR absorption frequencies of the olefin parts ofthe molecule shift to the higher magnetic field by 0.3 and 0.7 ppm. Thesalt was re-dispersed in 20 g of dioxane and a solution of 5.5 g ofethyl chloroformate in 20 g of dioxane was added dropwise to the slurryin 3 hours at 20° C. The crude product was evaporated in vacuo and theresidue was purified by column chromatography, thereby obtaining 3.1 gof ethyl n-methacrylolycarbamate.

Example 8-21

The unsaturated carbamic acid esters were synthesized by using thesimilar method in Example 1 from the starting materials in Table 1 usingthe quantity of the materials as are listed in the table. The results(the products and yields) are shown in Table 1.

Example 22

To the solution of 8.9 g of ethyl carbamate in 100 g of THF, 11.2 g ofpotassium t-butoxide was mixed and the reaction mixture was stirred for1 hour at 60° C. The resulting slurry was added dropwise to the solutionof 5.43 g of methacryloyl acid chloride in 50 g of THF heated at 60° C.in 2 hours. After removing THF by vacuum evaporation, the residue wasextracted with 1000 ml of water and 500 ml of ethyl acetate. The organicphase was concentrated in vacuo and the residue was subjected to columnchromatography for purification, thereby isolating 1.0 g of ethylmethacryloylcarbamate.

Example 23

To the solution of 8.9 g of ethyl carbamate in 50 g of o-xylene, aslurry of 2.2 g of NaH in 20 g of xylene was added dropwise in 30minutes, followed by stirring for additional 3 hours at 50° C. Then asolution of 10.5 g of methacryloyl chloride in 30 g of xylene was addeddropwise to the reaction mixture and the solution was stirred for 1 hourat 60° C. The resultant white precipitate were filtered off and thefiltrate was concentrated. The residue was subjected to columnchromatography for purification, thereby obtaining 6.1 g of ethylN-methacryloylcarbamate.

    TABLE 1        Kind of Amount Kind of  Amount of Kind of Amount    Example amide of     amide acid chloride solvent acid chloride base of base Product Yield     m.p.      8 Methacrylamide 3.0 g chloroformicacid2-ethylhexylester Dioxane 8.1 g     Sodiumethoxide 4.79 g      ##STR14##      2.5 g Viscosity800 cp.      9 Methacrylamide 2.0 g chloroformicacidisopropylester THF 3.44 g     Sodiumethoxide 3.20 g      ##STR15##      2.0 g 68-69   10 Methacrylamide 2.0 g chloroformic acid isobutylester     Dioxane 4.28 g Sodiumethoxide 3.20 g      ##STR16##      2.1 g 41-43   11 Methacrylamide 2.0 g chloroformicacidbenzylester     Dioxane 4.00 g Sodiumethoxide      3.2 g     ##STR17##      2.5 g 109-110   12 Methacrylamide 2.0 g chloroformicacidpropylester     Dioxane 3.08 g Potassiumt-butoxide      5.3 g     ##STR18##      3.0 g 68-69   13 Methacrylamide 2.0 g chloroformicacidpropalgylester     Dioxane 3.3 g Potassiumt-butoxide      5.3 g     ##STR19##      1.1 g 92-94   14 Methacrylamide 2.0 g chloroformicacidallylester DMF     3.13 g Potassiumt-butoxide      5.3 g     ##STR20##      2.5 g 43.5   15 Methacrylamide 12.5 g chloroformicacidethoxyethylester     Dioxane 22.5 g Sodiumethoxide      30 g     ##STR21##      10.0 g 91-92       16 Methacrylamide 12.5 g chloroformicacidbutoxyethylester Methyl-isobut     ylketone 26.7 g Sodiumethoxide      10 g     ##STR22##      15.3 g 27-28       17 Methacrylamide 12.5 g chloroformicacidacetylmethyl ester THF 21.6 g S     odiumethoxide      20 g     ##STR23##      10.0 g 84-86       18 Methacrylamide 12.5 g chloroformicacidmethoxycarbonylmethyl ester     Diethylether 22.5 g Sodiumethoxide      20 g     ##STR24##      14.0 g 80-82       19 Methacrylamide 12.5 g chloroformicacidtetrahydro-furfurylester     Dioxane 36.5 g Sodiumethoxide      30 g     ##STR25##      11.0 g 68-70   20 Acrylamide 10.4 g chloroformicacidethylester Dioxane     13.3 g Sodiumethoxide      20 g     ##STR26##      10.0 g 68-71   21 Acrylamide 10.4 g chloroformicacidbutoxyethylester     Dioxane 20.3 g Sodiumethoxide      20 g     ##STR27##      10.0 g

What is claimed is:
 1. A process for producing unsaturated carbamic acidesters represented by the following general formula of ##STR28## whichcomprises reacting urethane derivatives represented by the generalformula of ##STR29## with metallic bases selected from the groupconsisting of metallic hydroxides, metallic carbonates, metallichydrides, metallic alkylates, metallic alkoxide compounds and mixturesthereof in inert solvents, wherein the metal of the metallic base isselected from the group consisting of sodium, potassium, calcium,magnesium, aluminum, lithium and a mixture thereof, which reaction isfollowed by the reaction with unsaturated acid halides represented bythe following general formula: ##STR30## wherein R denotes a hydrogenatom or a lower alkyl group, R¹ denotes alkyl, cycloalkyl, allyl,aralkyl, alkaryl, alkenyl or alkynyl groups having carbon numbers of 1to 27 and 48, which may be substituted by halogen or may be substitutedby a substituent directly or through carbonyl, ether or thioether groupsand X denotes a halogen atom.
 2. The process according to claim 1wherein said urethane derivatives are selected from ethyl carbamate,propyl carbamate, butyl carbamate, sec-butyl carbamate, butoxyethylcarbamate and ethoxyethyl carbamate.
 3. The process according to claim 1wherein said metallic bases are present in an amount within the range of1 to 10 equivalent based on one equivalent of the unsaturated urethanederivatives.
 4. The process according to claim 1 wherein said inertsolvents have a dielectric constant within the range of 3 to
 40. 5. Theprocess according to claim 4 wherein said inert solvents are selectedfrom tetrahydrofuran (THF), dioxane, methyl isobutyl ketone,dichlorobenzene and dimethyl formamide (DMF).
 6. The process accordingto claim 1 wherein the reaction between the urethane derivatives (3) andthe metallic bases is conducted at a temperature of -10° to 120° C. for0.5 to 10 hours.
 7. The process according to claim 1 wherein saidunsaturated acid halides are added without isolating the reactionproduct between the urethane derivatives (3) and the metallic bases. 8.The process according to claim 1 wherein said unsaturated acid halidesare selected from acryloyl halide and methacryloyl halide.
 9. Theprocess according to claim 1 wherein the reaction of the unsaturatedacid halides is conducted -20° to 100° C. for 0.5 to 15 hours.
 10. Theprocess according to claim 1, wherein R¹ denotes alkyl, cycloalkyl,allyl, aralkyl, alkaryl, alkenyl or alkynyl groups having carbon numbersof 1 to 27 and 48 and having halogen substituents.
 11. The processaccording to claim 1, wherein R¹ denotes alkyl, cycloalkyl, allyl,aralkyl, alkaryl, alkenyl or alkynyl groups having carbon numbers of 1to 27 and 48, and having a substituent group which is bonded directly tosaid R¹ group or through carbonyl, ether or thioether groups.
 12. Theprocess according to claim 1, wherein the inert solvent is an organicsolvent.